code: def backward(ctx, dy):
      x, alpha = ctx.saved_tensors
  
      dx = dy.clone()
      dx[x < 0] = 0
      dx[x > alpha] = 0
  
      dalpha = dy.clone()
      dalpha[x <= alpha] = 0
  
      return dx, torch.sum(dalpha)
  
file_path: ignite/examples/cifar10_qat/pact.py
imports: import torch
  import torch.nn
label_desc: Use image node_id 2 for calling the PACTClip obj's underlying member method code with example usage: obj.backward(ctx, dy) and returns: dx,  torch